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A backward compatibility package for PIAX
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/*
* FragmentationTransport.java
*
* Copyright (c) 2012-2015 National Institute of Information and
* Communications Technology
*
* You can redistribute it and/or modify it under either the terms of
* the AGPLv3 or PIAX binary code license. See the file COPYING
* included in the PIAX package for more in detail.
*
* $Id: FragmentationTransport.java 718 2013-07-07 23:49:08Z yos $
*/
package org.piax.gtrans.util;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import org.piax.common.Endpoint;
import org.piax.common.ObjectId;
import org.piax.common.TransportId;
import org.piax.gtrans.Channel;
import org.piax.gtrans.ChannelTransport;
import org.piax.gtrans.GTransConfigValues;
import org.piax.gtrans.IdConflictException;
import org.piax.gtrans.ProtocolUnsupportedException;
import org.piax.gtrans.ReceivedMessage;
import org.piax.gtrans.TransOptions;
import org.piax.gtrans.Transport;
import org.piax.gtrans.impl.BinaryJsonabilityException;
import org.piax.gtrans.impl.ExceededSizeException;
import org.piax.gtrans.impl.MessageBinaryJsonner;
import org.piax.gtrans.impl.NestedMessage;
import org.piax.gtrans.impl.OneToOneMappingTransport;
import org.piax.util.ByteBufferUtil;
import org.piax.util.ByteUtil;
import org.piax.util.MersenneTwister;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
*/
public class FragmentationTransport extends
OneToOneMappingTransport {
/*--- logger ---*/
private static final Logger logger =
LoggerFactory.getLogger(FragmentationTransport.class);
private static final Random rand = new MersenneTwister();
private final Fragments frags = new Fragments();
private int msgId = rand.nextInt(Integer.MAX_VALUE);
public FragmentationTransport(TransportId transId, ChannelTransport lowerTrans)
throws IdConflictException, IOException {
super(transId, lowerTrans);
}
@Override
public synchronized void fin() {
super.fin();
lowerTrans.fin();
frags.fin();
}
@Override
public int getMTU() {
return GTransConfigValues.MAX_MSG_SIZE;
}
/**
* フラグメント化したパケットを識別するためのmsgIdを採番する。
* msgIdには、1～2147483647の番号を巡回的に使用する。
* msgId == 0 はフラグメント化の必要のないパケットのmsgIdとして使用する。
*
* @return 採番したmsgId
*/
private synchronized int newMsgId() {
if (msgId < Integer.MAX_VALUE) msgId++;
else msgId = 1;
return msgId;
}
/**
* 与えられたbyte列をlowerMTUのサイズ合った複数のbyte列に分割する
*
* @param msg
* @return
*/
private List partitioning(ByteBuffer msg) {
List flist = new ArrayList();
int lowerMsgSize = lowerTrans.getMTU() - Fragments.PACKET_HEADER_SIZE;
int msgLen = msg.remaining();
int msgId = 0;
int pNum = 1;
if (msgLen > lowerMsgSize) {
msgId = newMsgId();
pNum = (msgLen - 1) / lowerMsgSize + 1;
}
/*
* 長さ0のメッセージの送信も考慮
*/
for (int i = 0; i < pNum; i++) {
int boff = msg.arrayOffset() + msg.position() + i * lowerMsgSize;
int blen;
if (i == pNum - 1) {
blen = msgLen - i * lowerMsgSize;
} else {
blen = lowerMsgSize;
}
byte[] pac = frags.newPacketBytes(msgId, i, pNum, msg.array(), boff, blen);
if (logger.isDebugEnabled()) {
logger.debug("fragPacket msgId:{} i:{} len:{}", msgId, i, pac.length);
logger.trace("fragPacket:{}", ByteUtil.dumpBytes(pac));
}
flist.add(pac);
}
return flist;
}
@Override
protected void lowerSend(ObjectId sender, ObjectId receiver, E dst,
NestedMessage nmsg, TransOptions opts) throws ProtocolUnsupportedException, IOException {
ByteBuffer bb;
try {
bb = MessageBinaryJsonner.serialize(nmsg);
} catch (BinaryJsonabilityException e) {
logger.error("", e);
return;
} catch (ExceededSizeException e) {
throw new IOException(e);
}
IOException excep = null;
for (byte[] _msg : partitioning(bb)) {
try {
getLowerTransport().send(sender, receiver, dst, _msg);
} catch (IOException e) {
excep = e;
}
}
if (excep != null) {
throw excep;
}
}
@Override
protected void lowerChSend(Channel ch, NestedMessage nmsg) throws IOException {
ByteBuffer bb;
try {
bb = MessageBinaryJsonner.serialize(nmsg);
} catch (BinaryJsonabilityException e) {
logger.error("", e);
return;
} catch (ExceededSizeException e) {
throw new IOException(e);
}
for (byte[] _msg : partitioning(bb)) {
ch.send(_msg);
}
}
protected boolean useReceiverThread(int numProc) {
return false;
}
/**
* 受信した分割メッセージから、元のメッセージの構成を試みる。
* 再構成できた場合は、元のメッセージのbyte列を返す。再構成できなかった場合はnullが返される。
*
* @param from
* @param msg
* @return
*/
private ByteBuffer defragments(Endpoint from, byte[] pac) {
int len = pac.length;
Fragments.FragmentPacket fpac = new Fragments.FragmentPacket(pac, len);
if (logger.isDebugEnabled()) {
logger.debug("fragPacket tag:{} seq:{} len:{}",
frags.getTag(from, fpac.msgId), fpac._seq, len);
logger.trace("fragPacket:{}", ByteUtil.dumpBytes(pac, 0, len));
}
ByteBuffer _msg = null;
if (fpac.msgId == 0) {
_msg = ByteBufferUtil.byte2Buffer(fpac.bbuf, fpac.boff, fpac.blen);
} else {
_msg = frags.put(from, fpac);
}
if (_msg != null) {
logger.debug("defrag done: rsv bytes:{}", _msg.remaining());
}
return _msg;
}
@Override
public void onReceive(Channel lowerCh) {
OneToOneChannel ch = null;
NestedMessage nmsg = null;
synchronized (lowerCh) {
/*
* lowerCh.receive(0)で受理したメッセージを、ch.putReceiveQueueへ渡す順序を
* 保存するため、synchronized にしている
*/
byte[] b = (byte[]) lowerCh.receive();
if (b == null) {
logger.error("null message received");
return;
}
// lowerChとそれに対応するchannelのgetRemoteは一致するので、これでOK
ByteBuffer _msg = defragments(lowerCh.getRemote(), b);
if (_msg == null) return;
try {
nmsg = MessageBinaryJsonner.deserialize(_msg);
if (nmsg == null) {
logger.error("null message received");
return;
}
ch = super._putReceiveQueue(lowerCh, nmsg);
} catch (BinaryJsonabilityException e) {
logger.error("", e);
}
}
if (ch != null && nmsg != null) {
super._onReceive(ch, nmsg);
}
}
@Override
public void onReceive(Transport trans, ReceivedMessage rmsg) {
ByteBuffer _msg = defragments(rmsg.getSource(), (byte[]) rmsg.getMessage());
if (_msg == null) return;
try {
NestedMessage nmsg = MessageBinaryJsonner.deserialize(_msg);
super.onReceive(trans,
new ReceivedMessage(rmsg.getSender(), rmsg.getSource(), nmsg));
} catch (BinaryJsonabilityException e) {
logger.error("", e);
}
}
}